Semiconductor device

ABSTRACT

A semiconductor device includes a package substrate having a plurality of external connection terminals disposed on a first surface thereof and a plurality of internal connection terminals disposed on a second surface thereof and electrically connected with corresponding one of the external connection terminals, a first semiconductor chip stacked over the second surface of the package substrate and having a first flag pad for providing first information and a first internal circuit for adjusting a parameter by a first correction value in response to the first information provided from the first flag pad, and a second semiconductor chip stacked over the first semiconductor chip and having a second flag pad for providing second information and a second internal circuit for adjusting the parameter by a second correction value in response to the second information provided from the second flag pad.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application claims priority of Korean Patent Application No.10-2011-0011484, filed on Feb. 9, 2011, which is incorporated herein byreference in its entirety.

BACKGROUND

1. Field

Exemplary embodiments of the present invention relate to a semiconductordesign technology, and more particularly, to an AC parameter controltechnology of a semiconductor device.

2. Description of the Related Art

In the present specification, a semiconductor memory device will beexplained for example.

In general, a semiconductor memory device such as a DRAM is packaged bystacking a plurality of semiconductor chips (or dies) to achieve a largecapacity of data storage in a limited area. When compared to asemiconductor memory device having a single semiconductor chip packaged(a single die package: SDP), in a semiconductor memory device havingplural semiconductor chips stack-packaged, e.g. a dual die package (DDP)having two chips or a quad die package (QDP) having four chips, bondingwires may differ in length for respective stacked semiconductor chips.

FIG. 1 is a side view schematically illustrating a semiconductor memorydevice (DDP) in which two semiconductor chips are stack-packaged.

Referring to FIG. 1, a bonding wire W1 for connecting a packagesubstrate with the semiconductor chip stacked first on the packagesubstrate may be shorter than a bonding wire W2 for connecting thepackage substrate with the semiconductor chip stacked second over thepackage substrate. Therefore, when signals are outputted from therespective semiconductor chips for the same use, timing differences arecaused in the signals due to differences in the lengths of the bondingwires W1 and W2. That is to say, the signal outputted from the firststacked semiconductor chip and the signal outputted from the secondstacked semiconductor chip are finally transmitted to an externalcontroller at different times due to different positional conditions.

For example, in a semiconductor memory device using a delay locked loop(DLL), data strobe signals are transferred from a plurality of stackedsemiconductor chips through bonding wires and are finally provided to anexternal controller through a package substrate. At this time, the datastrobe signal outputted from a semiconductor chip stacked at the bottomis provided to the external controller through a relatively shortbonding wire, and the data strobe signal outputted from a semiconductorchip stacked at the top is provided to the external controller through arelatively long bonding wire. Since different delay values are appliedto the respective data strobe signals outputted from the plurality ofstacked semiconductor chips due to differences in the lengths of thebonding wires, the respective data strobe signals reach the externalcontroller at different times. A parameter tDQSCK that represents a skewbetween an external clock signal and a data strobe signal is prescribedin a specification for a proper operation of a semiconductor memorydevice. In this regard, if the parameter tDQSCK goes beyond a definedrange due to different delay values as described above, thesemiconductor memory device may malfunction in a read operation.

In order to prevent the above malfunction, the delay amounts of DLLsincluded in respective semiconductor chips may be corrected incorrespondence to positional conditions. That is to say, in theconventional art, the delay amounts of the DLLs included in theremaining stacked semiconductor chips are corrected based on the delayamount of the DLL included in a lowermost semiconductor chip. To thisend, correction circuits are provided in the remaining semiconductorchips excluding the lowermost semiconductor chip. Fuse circuits may beused as the correction circuits, and the delay amounts of the DLLs arecorrected using the output signals of the fuse circuits through a fusecutting process. However, in the case where the correction circuits areprovided as described above, since an additional process such as thefuse cutting process is to be performed, the manufacturing costsincrease and the manufacturing period is lengthened. Moreover, since thesemiconductor chips (the upper stacked semiconductor chips) with thecorrection circuits and the semiconductor chip (the lowermostsemiconductor chip) without a correction circuit are stack-packaged, therespective chips are to be manufactured through different maskpatterning processes. Hence, the manufacturing costs and themanufacturing time may further increase.

SUMMARY

An embodiment of the present invention is directed to a semiconductordevice in which AC parameters tDQSCK of a plurality of stackedsemiconductor chips are controlled within a defined range and all theplurality of stacked semiconductor chips are manufactured through thesame mask patterning process.

Another embodiment of the present invention is directed to asemiconductor device capable of controlling AC parameters tDQSCK of aplurality of stacked semiconductor chips with a minimized area.

In accordance with an embodiment of the present invention, asemiconductor device includes: at least one flag pad configured toprovide chip stack information for a stack sequence of semiconductorchips; and an internal circuit configured to adjust a parameter of thesemiconductor device in response to at least one of the chip stackinformation provided from the flag pad.

In accordance with another embodiment of the present invention, asemiconductor device includes: a package substrate having a plurality ofexternal connection terminals disposed on a first surface thereof and aplurality of internal connection terminals disposed on a second surfacethereof and electrically connected with corresponding one of theexternal connection terminals; a first semiconductor chip stacked overthe second surface of the package substrate, and having a first flag padfor providing first information and a first internal circuit foradjusting a parameter of the semiconductor device by a first correctionvalue in response to the first information provided from the first flagpad; and a second semiconductor chip stacked over the firstsemiconductor chip, and having a second flag pad for providing secondinformation and a second internal circuit for adjusting the parameter bya second correction value in response to the second information providedfrom the second flag pad.

In accordance with yet another embodiment of the present invention, asemiconductor device includes: at least one first pad configured toprovide wafer test information at a wafer level of the semiconductordevice and provide chip stack information for a stack sequence ofsemiconductor chips at a package level of the semiconductor device; atleast one test circuit configured to perform a test operation inresponse to the wafer test information provided from the first pad atthe wafer level; and an internal circuit configured to adjust aparameter of the semiconductor device in response to the chip stackinformation provided from the first pad at the package level.

In accordance with still another embodiment of the present invention, asemiconductor device includes: a package substrate having a plurality ofexternal connection terminals disposed on a first surface thereof and aplurality of internal connection terminals disposed on a second surfacethereof and electrically connected with corresponding one of theexternal connection terminals; a first semiconductor chip stacked overthe second surface of the package substrate, and having a first pad forproviding first wafer test information at a wafer level of thesemiconductor device and providing first chip stack information for astack sequence of the first semiconductor chip at a package level of thesemiconductor device, a first test circuit for performing a testoperation in response to the first wafer test information provided fromthe first pad at the wafer level, and a first internal circuit foradjusting a parameter of the semiconductor device by a first correctionvalue in response to the first chip stack information provided from thefirst pad at the package level; and a second semiconductor chip stackedover the first semiconductor chip, and having a second pad for providingsecond wafer test information at the wafer level and providing secondchip stack information for a stack sequence of the second semiconductorchip at the package level, a second test circuit for performing a testoperation in response to the second wafer test information provided fromthe second pad at the wafer level, and a second internal circuit foradjusting the parameter by a second correction value in response to thesecond chip stack information provided from the second pad at thepackage level.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side view schematically illustrating a stack-packagedsemiconductor memory device (DDP).

FIG. 2 is a plan view illustrating a package substrate and a firstsemiconductor chip first stacked on the package substrate in asemiconductor memory device (DDP) in accordance with a first embodimentof the present invention.

FIG. 3 is a block diagram illustrating an exemplary embodiment of thefirst internal circuit shown in FIG. 2.

FIG. 4 is a block diagram illustrating an exemplary embodiment of thefirst delay locked loop shown in FIG. 3.

FIG. 5 is a plan view illustrating the package substrate and a secondsemiconductor chip second stacked over the package substrate in thesemiconductor memory device (DDP) in accordance with the firstembodiment of the present invention.

FIG. 6 is a block diagram illustrating an exemplary embodiment of thesecond internal circuit shown in FIG. 5.

FIG. 7 is a plan view illustrating a package substrate and a firstsemiconductor chip first stacked on the package substrate in asemiconductor memory device (DDP) in accordance with a second embodimentof the present invention.

FIG. 8 is a block diagram illustrating an exemplary embodiment of thefirst circuit block shown in FIG. 7.

FIG. 9 is a block diagram illustrating an exemplary embodiment of thefirst test circuit shown in FIG. 8.

FIG. 10 is a circuit diagram illustrating an exemplary embodiment of thefirst transfer unit shown in FIG. 9.

FIG. 11 is a block diagram illustrating an exemplary embodiment of thefirst internal circuit shown in FIG. 8.

FIG. 12 is a block diagram illustrating an exemplary embodiment of thefirst delay locked loop shown in FIG. 11.

FIG. 13 is a plan view illustrating the package substrate and a secondsemiconductor chip second stacked over the package substrate in thesemiconductor memory device (DDP) in accordance with the secondembodiment of the present invention.

FIG. 14 is a block diagram illustrating an exemplary embodiment of thesecond circuit block shown in FIG. 13.

FIG. 15 is a block diagram illustrating an exemplary embodiment of thesecond test circuit shown in FIG. 14.

FIG. 16 is a circuit diagram illustrating an exemplary embodiment of thesecond transfer unit shown in FIG. 15.

FIG. 17 is a block diagram illustrating an exemplary embodiment of thesecond internal circuit shown in FIG. 14.

DETAILED DESCRIPTION

Exemplary embodiments of the present invention will be described belowin more detail with reference to the accompanying drawings. The presentinvention may, however, be embodied in different forms and should not beconstrued as limited to the embodiments set forth herein. Rather, theseembodiments are provided so that this disclosure will be thorough andcomplete, and will fully convey the scope of the present invention tothose skilled in the art. Throughout the disclosure, like referencenumerals refer to like parts throughout the various figures andembodiments of the present invention.

In the embodiments of the present invention, a semiconductor memorydevice (dual die package: DDP), in which two semiconductor chips arestacked on a package substrate, will be exemplified for the sake ofconvenience in explanation. Also, in order to clearly show the subjectmatters of the present invention, a semiconductor chip first stacked ona package substrate and a semiconductor chip second stacked over thepackage substrate will be separately described.

First Embodiment

First, FIG. 2 is a plan view illustrating a package substrate 110 and afirst semiconductor chip 120 first stacked on the package substrate 110in a semiconductor memory device (DDP) in accordance with a firstembodiment of the present invention.

Referring to FIG. 2, the semiconductor memory device (DDP) in accordancewith the first embodiment of the present invention includes a packagesubstrate 110 including first internal connection terminals 112, a firstsemiconductor chip 120 first stacked on the package substrate 110 andincluding a first signal pad 120A for outputting a first data strobesignal DQS1, and a first wire W11 electrically connecting the firstinternal connection terminal 112 with the first signal pad 120A.

The package substrate 110 has a lower surface, on which a plurality ofexternal connection terminals (not shown) for interfacing with anexternal controller (not shown) using various signals and power aredisposed, and an upper surface on which a plurality of internalconnection terminals for interfacing with the first semiconductor chip120 and a second semiconductor chip 140 to be described later usingvarious signals and power are disposed. For reference, correspondingterminals of the plurality of external connection terminals and theplurality of internal connection terminals are electrically connectedwith each other in a routing method.

The first semiconductor chip 120 includes a first flag pad 120Bconfigured to provide first chip stack information CSI1 corresponding toa stack sequence of semiconductor chips and a first internal circuit 121configured to correct or adjust an AC parameter based on the first chipstack information CSI1 provided from the first flag pad 120B. The ACparameter means a parameter tDQSCK that indicates a skew between anexternal clock signal and a data strobe signal in a read operation.

The first flag pad 120B is additionally provided not to be connectedwith any internal connection terminal. Accordingly, the first flag pad120B is in a floating state, and the first chip stack information CSI1has a high impedance (Hi-Z) value.

In order to correct or adjust the AC parameter tDQSCK by a firstcorrection value based on the first chip stack information CSI1, thefirst internal circuit 121 outputs the first data strobe signal DQS1 onwhich a first delay value corresponding to the first correction value isreflected, to the first signal pad 120A.

FIG. 3 is a block diagram illustrating the internal configuration of thefirst internal circuit 121 shown in FIG. 2, and FIG. 4 is a blockdiagram illustrating an exemplary embodiment of a first delay lockedloop 121_3 shown in FIG. 3.

Referring to FIG. 3, the first internal circuit 121 includes a firstbuffer unit 121_1, the first delay locked loop 121_3, and a first datastrobe signal generation unit 121_5.

The first buffer unit 121_1 is configured to receive the first chipstack information CSI1 and output first internal chip stack informationIN_CSI1. The first buffer unit 121_1 may output the first internal chipstack information IN_CSI1 of a logic low level when the first chip stackinformation CSI1 of a high impedance (Hi-Z) value is inputted.

The first delay locked loop 121_3 is configured to control the delayvalue of the first replica delay (see FIG. 4) included therein inresponse to the first internal chip stack information IN_CSI1, delay anexternal clock signal EX_CLK by the controlled delay value, and output afirst delayed clock signal DLL_CLK1. Referring to FIG. 4, the firstdelay locked loop 121_3 includes a first delay line 121_31 configured todelay the external clock signal EX_CLK by a delay time for delay lockingand output the delay-locked first delayed clock signal DLL_CLK1, a firstreplica delay 121_33 configured to delay the first delayed clock signalDLL_CLK1 by a delay value acquired by modeling an internal delay elementand output a first feedback clock signal FB_CLK1 in which a first delayvalue is additionally included in the acquired delay value (i.e., adefault value) in response to the first internal chip stack informationIN_CSI1, a first phase comparison section 121_35 configured to comparethe phases of the external clock signal EX_CLK and the first feedbackclock signal FB_CLK1, and a first delay amount control section 121_37configured to generate a first control signal DELY_CTRL1 for controllingthe delay amount of the first delay line 121_31 in response to an outputsignal UP/DOWN of the first phase comparison section 121_35.

Referring back to FIG. 3, the first data strobe signal generation unit121_5 is configured to generate the first data strobe signal DQS1 inresponse to the first delayed clock signal DLL_CLK1. Accordingly, thefirst data strobe signal DQS1 has the same phase as the first delayedclock signal DLL_CLK1.

FIG. 5 is a plan view illustrating the package substrate 110 and thesecond semiconductor chip 140 second stacked over the package substrate110, that is, on the first semiconductor chip 120, in the semiconductormemory device (DDP) in accordance with the first embodiment of thepresent invention.

Referring to FIG. 5, the semiconductor memory device (DDP) in accordancewith the first embodiment of the present invention includes the packagesubstrate 110 including first and second internal connection terminals112 and 114, the second semiconductor chip 140 second stacked over thepackage substrate 110 and including a second signal pad 140A foroutputting a second data strobe signal DQS2 and a second flag pad 140Bfor providing second chip stack information CSI2 corresponding to astack sequence of semiconductor chips, a second wire W12 configured toelectrically connect the first internal connection terminal 112 with thesecond signal pad 140A, and a third wire W13 configured to electricallyconnect the second internal connection terminal 114 with the second flagpad 140B. The second internal connection terminals 114 are terminals forsupplying a power supply voltage VDD applied from the externalcontroller.

As described above, the package substrate 110 functions to transfersignals and powers between the first and second semiconductor chips 120and 140 and the external controller.

The second semiconductor chip 140 includes a second internal circuit 141configured to correct or adjust a skew tDQSCK between the external clocksignal and the second data strobe signal DQS2 in response to the secondchip stack information CSI2 provided from the second flag pad 140B.

The second flag pad 140B is additionally provided, like the first flagpad 120B, but is connected with the second internal connection terminal114 through the third bonding wire W13, unlike the first flag pad 120B.Accordingly, the second flag pad 140B is supplied with the power supplyvoltage VDD through the third bonding wire W13, and thus, the secondchip stack information CSI2 has a logic high level.

The second internal circuit 141 outputs the second data strobe signalDQS2, which is corrected by a second correction value, to the secondsignal pad 140A in response to the second chip stack information CSI2.

FIG. 6 is a block diagram illustrating the internal configuration of thesecond internal circuit 141.

Referring to FIG. 6, the second internal circuit 141 includes a secondbuffer unit 141_1, a second delay locked loop 141_3, and a second datastrobe signal generation unit 141_5.

The second buffer unit 141_1 is configured to receive the second chipstack information CSI2 and output second internal chip stack informationIN_CSI2. The second buffer unit 141_1 may output the second internalchip stack information IN_CSI2 of a logic high level when the first chipstack information CSI1 of a logic high level is inputted.

The second delay locked loop 141_3 is configured to control the delayvalue of the first replica delay (not shown) included therein inresponse to the second internal chip stack information IN_CSI2, delaythe external clock signal EX_CLK by the controlled delay value, andoutput a second delayed clock signal DLL_CLK2. Since the second delaylocked loop 141_3 has the same configuration as the first delay lockedloop 121_3 described above (see FIG. 4), detailed description thereofwill be omitted herein. For reference, while the second replica delayincluded in the second delay locked loop 141_3 is set to have a delayvalue acquired through modeling of an internal delay element as adefault, a second delay value is additionally included in the set delayvalue in response to the second internal chip stack information IN_CSI2.

The second data strobe signal generation unit 141_5 is configured togenerate the second data strobe signal DQS2 in response to the seconddelayed clock signal DLL_CLK2. Accordingly, the second data strobesignal DQS2 has the same phase as the second delayed clock signalDLL_CLK2.

Hereafter, operations of the semiconductor memory device (DDP)configured as mentioned above will be described.

In the first embodiment of the present invention, the case of correctingthe AC parameter tDQSCK of the second semiconductor chip 140 based onthe AC parameter tDQSCK of the first semiconductor chip 120 will beexemplified. That is, a second correction value has a predeterminedvalue while a first correction value is ‘0’. In other words, since thefirst and second bonding wires W11 and W12 having different lengths havedifferent delay elements, a series of operations for compensating forthe delay element of the second bonding wire W12 are performed such thatthe delay element of the second bonding wire W12 having a relativelylong length can correspond to the delay element of the first bondingwire W11 having a relatively short length.

First, since the first flag pad 120B of the first semiconductor chip 120is not connected with any internal connection terminal which is disposedon the package substrate 110, the first flag pad 120B is in a floatingstate. According to this fact, the first chip stack information CSI1provided through the first flag pad 120B has a high impedance (Hi-Z)value, and the first internal circuit 121 provided with the first chipstack information CSI1 outputs the first data strobe signal DQS1, onwhich only a modeled delay value is reflected, to the first signal pad120A.

Describing in detail the operations of the first internal circuit 121,the first buffer unit 121_1 outputs the first internal chip stackinformation IN_CSI1 of a logic low level in response to the first chipstack information CSI1 of the high impedance (Hi-Z) value. The firstdelay locked loop 121_3 maintains the delay value of the first replicadelay to have a preset default value in response to the first internalchip stack information IN_CSI1 of a logic low level, delay the externalclock signal EX_CLK by the maintained delay value, and outputs the firstdelayed clock signal DLL_CLK1. The first data strobe signal generationunit 121_5 generates the first data strobe signal DQS1 of the same phaseas the first delayed clock signal DLL_CLK1 in response to the firstdelayed clock signal DLL_CLK1, and the first data strobe signal DQS1 isoutputted to the first signal pad 120A.

The first data strobe signal DQS1 applied to the first signal pad 120Ais transferred to the first internal connection terminal 112 through thefirst bonding wire W11 and is finally transferred to the externalcontroller through the package substrate 110.

Since the second flag pad 140B of the second semiconductor chip 140 isconnected with the second internal connection terminal 114 disposed onthe package substrate 110, the second flag pad 140B is provided with thepower supply voltage VDD. According to this fact, the second chip stackinformation CSI2 provided through the second flag pad 140B has a logichigh level, and the second internal circuit 141 provided with the secondchip stack information CSI2 of the logic high level outputs the seconddata strobe signal DQS2, on which the second delay value as well as themodeled delay value is reflected, to the second signal pad 140A.

Describing in detail the operations of the second internal circuit 141,the second buffer unit 141_1 outputs the second internal chip stackinformation IN_CSI2 of a logic high level in response to the second chipstack information CSI1 of the logic high level. The second delay lockedloop 141_3 controls the delay value of the second replica delay to havethe summed value of a preset default value and the second delay value inresponse to the second internal chip stack information IN_CSI2 of thelogic high level, delays the external clock signal EX_CLK by thecontrolled delay value, and outputs the second delayed clock signalDLL_CLK2. The second data strobe signal generation unit 141_5 generatesthe second data strobe signal DQS2 of the same phase as the seconddelayed clock signal DLL_CLK2 in response to the second delayed clocksignal DLL_CLK2, and the second data strobe signal DQS2 is outputted tothe second signal pad 140A.

The second data strobe signal DQS2 applied to the second signal pad 140Ais transferred to the first internal connection terminal 112 through thesecond bonding wire W12 and is finally transferred to the externalcontroller through the package substrate 110.

The first and second data strobe signals DQS1 and DQS2 transferred tothe external controller in these ways have phases in which parameterstDQSCK indicating skews with respect to the external clock signal EX_CLKbecome the same. The reason to this resides in that, as described above,since the first data strobe signal DQS1 transferred through the firstbonding wire W11 of the relatively short length is a signal derived fromthe first delayed clock signal DLL_CLK1 on which only the preset delayvalue is reflected and the second data strobe signal DQS2 transferredthrough the second bonding wire W12 of the relatively long length is asignal derived from the second delayed clock signal DLL_CLK2 on whichthe second delay value as well as the preset delay value is reflected,the second data strobe signal DQS2 has a phase in which the delayelement of the second bonding wire W12 is compensated for.

According to the first embodiment of the present invention, even whenthe lengths of bonding wires vary depending upon a stack sequence ofsemiconductor chips, an AC parameter tDQSCK may be actively corrected.Therefore, the AC parameter tDQSCK may be controlled within a rangedefined in a specification.

Second Embodiment

A second embodiment of the present invention has a structure in which anarea is minimized when compared to the first embodiment. Namely, whileflag pads are additionally provided in the first embodiment, the secondembodiment has a structure in which probe test pads provided to be usedat a wafer level are utilized at a package level.

FIG. 7 is a plan view illustrating a package substrate 210 and a firstsemiconductor chip 220 first stacked on the package substrate 210 in asemiconductor memory device (DDP) in accordance with a second embodimentof the present invention.

Referring to FIG. 7, the semiconductor memory device (DDP) in accordancewith the second embodiment of the present invention includes the packagesubstrate 210 which includes first internal connection terminals 212,the first semiconductor chip 220 which is first stacked on the packagesubstrate 210 and includes a first signal pad 220A for outputting afirst data strobe signal DQS11, and a first wire W21 which electricallyconnects the first internal connection terminal 212 with the firstsignal pad 220A.

The package substrate 210 has a lower surface, on which a plurality ofexternal connection terminals (not shown) for interfacing with anexternal controller (not shown) using various signals and power aredisposed, and an upper surface on which a plurality of internalconnection terminals for interfacing with the first semiconductor chip220 and a second semiconductor chip 240 to be described below usingvarious signals and power are disposed. For reference, correspondingterminals of the plurality of external connection terminals and theplurality of internal connection terminals are electrically connectedwith each other in a routing method.

The first semiconductor chip 220 includes a first wafer burn-in test pad220B and a first circuit block 221.

The first wafer burn-in test pad 220B provides first wafer burn-in testinformation TM1 at a wafer level and provides first chip stackinformation CSI11 corresponding to a stack sequence of semiconductorchips at a package level. More specifically, at the wafer level, thefirst wafer burn-in test pad 220B is connected to a channel assigned toa probe test apparatus/equipment (not shown) and is applied with thefirst wafer burn-in test information TM1 from the probe test apparatus.The first wafer burn-in test pad 220B is a wafer test pad which is notgenerally used at the package level. In this regard, in the embodimentof the present invention, the first wafer burn-in test pad 220B is usedto provide the first chip stack information CSI11 at the package level.That is to say, the first wafer burn-in test pad 220B is not connectedwith any internal connection terminal in a floating state at the packagelevel, and due to this fact, the first chip stack information CSI11 hasa high impedance (Hi-Z) value.

The first circuit block 221 is configured to perform a predeterminedoperation in response to the first wafer burn-in test information TM1 orthe first chip stack information CSI11, and will be described in detailwith reference to FIG. 8.

FIG. 8 is a block diagram illustrating the internal configuration of thefirst circuit block 221 shown in FIG. 7.

Referring to FIG. 8, the first circuit block 221 includes a first testcircuit 221A configured to perform a wafer burn-in test operation inresponse to the first wafer burn-in test information TM1 provided fromthe first wafer burn-in test pad 220B at the wafer level and a firstinternal circuit 221B configured to correct or adjust an AC parameter bya first correction value in response to the first chip stack informationCSI11 provided from the first wafer burn-in test pad 220B at the packagelevel. The AC parameter means a parameter tDQSCK that indicates a skewbetween an external clock signal and a data strobe signal in a readoperation.

FIG. 9 is a block diagram of the first test circuit 221A shown in FIG.8, and FIG. 10 is an internal circuit diagram of a first transfer unit221A_3 shown in FIG. 9.

Referring to FIG. 9, the first test circuit 221A includes a first fusemodule 221A_1, the first transfer unit 221A_3 configured to selectivelytransfer the first wafer burn-in test information TM1 or the first chipstack information CSI11 in response to first fuse information F_OUT1outputted from the first fuse module 221A_1, and a first wafer burn-inlogic unit 221A_5 configured to generate a first wafer burn-in testcontrol signal WBI_CTRL1 in response to a first transfer signal F_SEL1selectively transferred from the first transfer unit 221A3. Such a firsttest circuit 221A is enabled at the wafer level and is disabled at thepackage level. Precisely, the first wafer burn-in logic unit 221A_5 isenabled at the wafer level and is disabled at the package level. To thisend, the first transfer unit 221A_3 may output the first transfer signalF_SEL1 for enabling the first wafer burn-in logic unit 221A_5 inresponse to the first wafer burn-in test information TM1 applied at thewafer level, and the first wafer burn-in logic unit 221A_5 may bedisabled by cutting the fuse (not shown) included in the first fusemodule 221A_1 as a probe test is completed. Referring to FIG. 10, thefirst transfer unit 221A_3 for determining whether to enable or disablethe first wafer burn-in logic unit 221A_5 in this way includes a firstNAND gate NAND1 for performing NAND operation on the first wafer burn-intest information TM1 or the first chip stack information CSI11 and thefirst fuse information F_OUT1 and a first inverter INV1 for invertingthe output signal of the first NAND gate NAND1 and outputting the firsttransfer signal F_SEL1.

FIG. 11 is a block diagram of the first internal circuit 221B shown inFIG. 8, and FIG. 12 is a block diagram illustrating an exemplaryembodiment of a first delay locked loop 221B_3 shown in FIG. 11.

Referring to FIG. 11, the first internal circuit 221B is configured tooutput a first data strobe signal DQS11 on which a first delay valuecorresponding to a first correction value is reflected, in order tocorrect or adjust an AC parameter tDQSCK by the first correction valuein response to the first chip stack information CSI11. The firstinternal circuit 221B includes a first buffer unit 221B_1, the firstdelay locked loop 221B_3, and a first data strobe signal generation unit221B_5. Since the first delay locked loop 221B_3 is disabled at thewafer level and is enabled at the package level in response to a firstenable signal TM_DIS1, the component elements of the first internalcircuit 221B will be described based on the operation of the packagelevel for the sake of convenience in explanation.

The first buffer unit 221B_1 is configured to receive the first chipstack information CSI11 and output first internal chip stack informationIN_CSI11. The first buffer unit 221B_1 may output the first internalchip stack information IN_CSI11 of a logic low level when the first chipstack information CSI11 of a high impedance (Hi-Z) value is inputted.

The first delay locked loop 221B_3 is configured to control the delayvalue of the first replica delay (see FIG. 12) included therein inresponse to the first internal chip stack information IN_CSI11, delay anexternal clock signal EX_CLK by the controlled delay value, and output afirst delayed clock signal DLL_CLK11. Referring to FIG. 12, the firstdelay locked loop 221B_3 includes a first delay line 221B_31 configuredto delay the external clock signal EX_CLK by a delay time for delaylocking and output the delay locked first delayed clock signalDLL_CLK11, a first replica delay 221B_33 configured to delay the firstdelayed clock signal DLL_CLK11 by a delay value acquired by modeling aninternal delay element as a default value and output a first feedbackclock signal FB_CLK11 in which the first delay value is additionallyincluded in the acquired delay value in response to the first internalchip stack information IN_CSI11, a first phase comparison section221B_35 configured to compare the phases of the external clock signalEX_CLK and the first feedback clock signal FB_CLK11, and a first delayamount control section 221B_37 configured to generate a first controlsignal DELY_CTRL11 for controlling the delay amount of the first delayline 221B_31 in response to an output signal UP/DOWN of the first phasecomparison section 221B_35.

Referring back to FIG. 11, the first data strobe signal generation unit221B_5 is configured to generate the first data strobe signal DQS11 inresponse to the first delayed clock signal DLL_CLK11. Accordingly, thefirst data strobe signal DQS11 has the same phase as the first delayedclock signal DLL_CLK11.

FIG. 13 is a plan view illustrating the package substrate 210 and asecond semiconductor chip 240 second stacked over the package substrate210, that is, over the first semiconductor chip 220, in thesemiconductor memory device (DDP) in accordance with the secondembodiment of the present invention.

Referring to FIG. 13, the semiconductor memory device (DDP) inaccordance with the second embodiment of the present invention includesthe package substrate 210 including first and second internal connectionterminals 212 and 214, the second semiconductor chip 240 second stackedover the package substrate 210 and including a second signal pad 240Aconfigured to output a second data strobe signal DQS12 and a secondwafer burn-in test pad 240B configured to provide second wafer burn-intest information TM2 at the wafer level and provide second chip stackinformation CSI12 corresponding to a stack sequence of semiconductorchips at the package level, a second wire W22 configured to electricallyconnect the first internal connection terminal 212 with the secondsignal pad 240A, and a third wire W13 configured to electrically connectthe second internal connection terminal 214 with the second waferburn-in test pad 240B. The second internal connection terminals 214 areterminals for supplying a power supply voltage VDD applied from theexternal controller. At the wafer level, the second wafer burn-in testpad 240B is connected to a channel assigned to a probe testapparatus/equipment (not shown) and is applied with the second waferburn-in test information TM2 from the probe test apparatus. Forreference, the second wafer burn-in test pad 240B is a wafer test padwhich is not generally used at the package level. In this regard, in theembodiment of the present invention, the second wafer burn-in test pad240B is used to provide the second chip stack information CSI12 at thepackage level. That is to say, because the second wafer burn-in test pad240B is connected with the second internal connection terminal 214through a third bonding wire W23 at the package level, the second waferburn-in test pad 240B is applied with the power supply voltage VDD fromthe second internal connection terminal 214, and due to this fact, thesecond chip stack information CSI12 has a logic high level.

As described above, the package substrate 210 functions to transfersignals and powers between the first and second semiconductor chips 220and 240 and the external controller.

The second semiconductor chip 240 includes a second circuit block 241configured to perform a predetermined operation in response to thesecond wafer burn-in test information TM2 or the second chip stackinformation C5112 provided from the second wafer burn-in test pad 240B.

FIG. 14 is a block diagram illustrating the internal configuration ofthe second circuit block 241 shown in FIG. 13.

Referring to FIG. 14, the second circuit block 241 includes a secondtest circuit 241A configured to perform a wafer burn-in test operationin response to the second wafer burn-in test information TM2 providedfrom the second wafer burn-in test pad 240B at the wafer level and asecond internal circuit 241B configured to correct or adjust an ACparameter by a second correction value in response to the second chipstack information CSI12 provided from the second wafer burn-in test pad240B at the package level. The AC parameter means a parameter tDQSCKthat indicates a skew between an external clock signal and a data strobesignal in a read operation.

FIG. 15 is a block diagram of the second test circuit 241A shown in FIG.14, and FIG. 16 is an internal circuit diagram of a second transfer unit241A_3 shown in FIG. 15.

Referring to FIG. 15, the second test circuit 241A includes a secondfuse module 241A_1, the second transfer unit 241A_3 configured toselectively transfer the second wafer burn-in test information TM2 orthe second chip stack information CSI12 in response to second fuseinformation F_OUT2 outputted from the second fuse module 241A_1, and asecond wafer burn-in logic unit 241A_5 configured to generate a secondwafer burn-in test control signal WBI_CTRL2 in response to a secondtransfer signal F_SEL2 selectively transferred from the second transferunit 241A_3. Such second test circuit 241A is enabled at the wafer leveland is disabled at the package level. Precisely, the second waferburn-in logic unit 241A_5 is enabled at the wafer level and is disabledat the package level. To this end, the second transfer unit 241A_3 mayoutput the second transfer signal F_SEL2 for enabling the second waferburn-in logic unit 241A_5 in response to the second wafer burn-in testinformation TM2 applied at the wafer level, and the second wafer burn-inlogic unit 241A_5 may be disabled by cutting the fuse (not shown)included in the second fuse module 241A_1 as a probe test is completed.Referring to FIG. 16, the second transfer unit 241A_3 for determiningwhether to enable or disable the second wafer burn-in logic unit 241A_5in this way includes a second NAND gate NAND2 for performing NANDoperation on the second wafer burn-in test information TM2 or the secondchip stack information CSI12 and the second fuse information F_OUT2 anda second inverter INV2 for inverting the output signal of the secondNAND gate NAND2 and outputting the second transfer signal F_SEL2.

FIG. 17 is a block diagram of the second internal circuit 241B shown inFIG. 14.

Referring to FIG. 17, the second internal circuit 241B is configured tooutput the second data strobe signal DQS12 on which a second delay valuecorresponding to a second correction value is reflected, in order tocorrect or adjust an AC parameter tDQSCK by the second correction valuein response to the second chip stack information CSI12. The secondinternal circuit 241B includes a second buffer unit 241B_1, the seconddelay locked loop 241B_3, and a second data strobe signal generationunit 241B_5. Since the second delay locked loop 241B_3 is disabled atthe wafer level and is enabled at the package level in response to asecond enable signal TM_DIS2, the component elements of the secondinternal circuit 241B will be described based on the operation of thepackage level for the sake of convenience in explanation.

The second buffer unit 241B_1 is configured to receive the second chipstack information CSI12 and output second internal chip stackinformation IN_CSI12. The second buffer unit 241B_1 may output thesecond internal chip stack information IN_CSI12 of a logic high levelwhen the second chip stack information CSI12 of a logic high level isinputted.

The second delay locked loop 241B_3 is configured to control the delayvalue of the second replica delay (not shown) included therein inresponse to the second internal chip stack information IN_CSI12, delaythe external clock signal EX_CLK by the controlled delay value, andoutput a second delayed clock signal DLL_CLK12. Since the second delaylocked loop 241B_3 has the same configuration as the first delay lockedloop 221B_3 described above (see FIG. 12), detailed description thereofwill be omitted herein. For reference, while the second replica delayincluded in the second delay locked loop 241B_3 is set to have a delayvalue modeled from an internal delay element as a default, the seconddelay value is additionally included in the set delay value in responseto the second internal chip stack information IN_CSI12.

The second data strobe signal generation unit 241B_5 is configured togenerate the second data strobe signal DQS12 in response to the seconddelayed clock signal DLL_CLK12. Accordingly, the second data strobesignal DQS12 and the second delayed clock signal DLL_CLK12 have the samephase.

Hereafter, operations of the semiconductor memory device (DDP) inaccordance with the second embodiment of the present invention,configured as mentioned above, will be described.

First, operations at the wafer level are described.

First, wafer burn-in tests are performed for the first and secondsemiconductor chips 220 and 240 at the wafer level. Since the waferburn-in tests for the first and second semiconductor chips 220 and 240are performed through the same procedure, only the wafer burn-in testfor the first semiconductor chip 220 will be representatively describedfor the sake of convenience in explanation.

The first wafer burn-in test pad 220B is connected to a channel assignedto a probe test apparatus and is applied with the first wafer burn-intest information TM1 through the assigned channel from the probe testapparatus. Then, the first transfer unit 221A_3 outputs the firsttransfer signal F_SEL1 of a logic high level to enable the first waferburn-in logic unit 221A_5 in response to the first fuse informationF_OUT1 and the first wafer burn-in test information TM1. Then, the firstwafer burn-in logic unit 221A_5 generates the first wafer burn-in testcontrol signal WBI_CTRL1 for performing the wafer burn-in test for banksBANK0 to BANK3 included in the first semiconductor chip 220. The firstinternal circuit 221B is disabled in response to the first enable signalTM_DIS1.

Thereafter, if the fuse included in the first fuse module 221A_1 is cutas the wafer burn-in test is completed, responding to the first fuseinformation F_OUT1 of a logic low level, the first transfer unit 221A_3outputs the first transfer signal F_SEL1 of a logic low level to disablethe first wafer burn-in logic unit 221A_5 regardless of any other inputsignals. Accordingly, the first wafer burn-in logic unit 221A_5 isdisabled.

Next, operations at the package level are described.

In the case of the package level, in the second embodiment of thepresent invention, in the same manner as in the first embodiment, thecase of correcting the AC parameter tDQSCK of the second semiconductorchip 240 based on the AC parameter tDQSCK of the first semiconductorchip 220 will be exemplified. That is, a second correction value has apredetermined value while a first correction value is ‘0’. In otherwords, since the first and second bonding wires W21 and W22 of differentlengths have different delay elements, a series of operations forcompensating for the delay element of the second bonding wire W22 areperformed such that the delay element of the second bonding wire W22having a relatively long length can correspond to the delay element ofthe first bonding wire W21 having a relatively short length.

First, since the first wafer burn-in test pad 220B of the firstsemiconductor chip 220 is not connected with any internal connectionterminal which is disposed on the package substrate 210, the first waferburn-in test pad 220B is in a floating state. According to this fact,the first chip stack information CSI11 provided through the first waferburn-in test pad 220B has a high impedance (Hi-Z) value, and the firstinternal circuit 221B provided with the first chip stack informationCSI11 outputs the first data strobe signal DQS11, on which only amodeled delay value is reflected, to the first signal pad 220A.

Describing in detail the operations of the first internal circuit 221,the first buffer unit 221B_1 outputs the first internal chip stackinformation IN_CSI11 of a logic low level in response to the first chipstack information CSI11 of the high impedance (Hi-Z) value. The firstdelay locked loop 221B_3 maintains the delay value of the first replicadelay to have a preset default value in response to the first internalchip stack information IN_CSI11 of a logic low level, delay the externalclock signal EX_CLK by the maintained delay value, and outputs the firstdelayed clock signal DLL_CLK11. The first data strobe signal generationunit 221B_5 generates the first data strobe signal DQS11 of the samephase as the first delayed clock signal DLL_CLK11 in response to thefirst delayed clock signal DLL_CLK11, and the first data strobe signalDQS11 is outputted to the first signal pad 220A.

The first data strobe signal DQS11 applied to the first signal pad 220Ais transferred to the first internal connection terminal 212 through thefirst bonding wire W21 and is finally transferred to the externalcontroller through the package substrate 210.

Since the second wafer burn-in test pad 240B of the second semiconductorchip 240 is connected with the second internal connection terminal 214disposed on the package substrate 210, it is provided with the powersupply voltage VDD. According to this fact, the second chip stackinformation CSI12 provided through the second wafer burn-in test pad240B has a logic high level, and the second internal circuit 241provided with the second chip stack information CSI12 of the logic highlevel outputs the second data strobe signal DQS2, on which a seconddelay value as well as the modeled delay value is reflected, to thesecond signal pad 240A.

Describing in detail the operations of the second internal circuit 241,the second buffer unit 241B_1 outputs the second internal chip stackinformation IN_CSI12 of a logic high level in response to the secondchip stack information CSI12 of the logic high level. The second delaylocked loop 241B_3 controls the delay value of the second replica delayto have the summed value of a preset default value and the second delayvalue in response to the second internal chip stack information IN_CSI12of the logic high level, delays the external clock signal EX_CLK by thecontrolled delay value, and outputs the second delayed clock signalDLL_CLK12. The second data strobe signal generation unit 241B_5generates the second data strobe signal DQS12 of the same phase as thesecond delayed clock signal DLL_CLK12 in response to the second delayedclock signal DLL_CLK12, and the second data strobe signal DQS12 isoutputted to the second signal pad 240A.

The second data strobe signal DQS12 applied to the second signal pad240A is transferred to the first internal connection terminal 212through the second bonding wire W22 and is finally transferred to theexternal controller through the package substrate 210.

The first and second data strobe signals DQS11 and DQS12 transferred tothe external controller in these ways have phases in which parameterstDQSCK indicating skews with respect to the external clock signal EX_CLKbecome the same. This reason to this resides in that, as describedabove, since the first data strobe signal DQS11 transferred through thefirst bonding wire W21 of the relatively short length is a signalderived from the first delayed clock signal DLL_CLK11 on which only thepreset delay value is reflected and the second data strobe signal DQS12transferred through the second bonding wire W22 of the relatively longlength is a signal derived from the second delayed clock signalDLL_CLK12 on which the second delay value as well as the preset delayvalue is reflected, the second data strobe signal DQS12 has a phase inwhich the delay element of the second bonding wire W22 is compensatedfor.

According to the second embodiment of the present invention, advantagesare provided in that an area can be minimized when compared to the firstembodiment. Also, even when the lengths of bonding wires vary dependingupon a stack sequence of semiconductor chips, an AC parameter tDQSCK maybe actively corrected. Therefore, the AC parameter tDQSCK may becontrolled within a range defined in a specification.

As is apparent from the above descriptions, the following effects may beachieved according to the embodiment in which flag pads are added andthe embodiment in which pads already provided are used.

First, in the case that the flag pads are added, because AC parameters(tDQSCK) of a plurality of stacked semiconductor chips are activelycorrected without an additional process, an erroneous operation can beprevented. For example, since an erroneous operation is prevented fromoccurring in a read operation of a semiconductor memory device,operational reliability and stability may be increased. Further, becausethe plurality of stacked semiconductor chips may be manufactured throughthe same mask patterning process, the manufacturing costs can be reducedand the manufacturing time can be shortened.

Next, in the case that the pads for other uses, e.g., test operations,are used, since pads are not additionally provided, the area of thesemiconductor chip may be minimized when compared to the case that theflag pads are added. Also, because the corresponding embodiment may beapplied to a semiconductor chip having a layout structure in which it isdifficult for pads to be added, excellent applicability can beaccomplished.

While the present invention has been described with respect to thespecific embodiments, it will be apparent to those skilled in the artthat various changes and modifications may be made without departingfrom the spirit and scope of the invention as defined in the followingclaims.

For example, while the semiconductor memory device (DDP) in which twosemiconductor chips are stack-packaged was exemplarily described in theembodiments of the present invention, it may be applied to asemiconductor memory device in which at least three semiconductor chipsare stack-packaged. In this case, at least two flag pads may be used,and the chip stack information provided through at least two flag padsmay be applied by being decoded for respective semiconductor chips.

Also, while a parameter (tDQSCK) indicating a skew between an externalclock signal and a data strobe signal was exemplarily described in theembodiments of the present invention, an AC parameter such as a datasetup time (tDS) and a data hold time (tDH) may be corrected.

Moreover, while it was exemplarily described in the embodiments of thepresent invention that the AC parameter of a second stacked secondsemiconductor chip is corrected based on a first semiconductor chipfirst stacked on a package substrate, the AC parameter of a firstsemiconductor chip may be corrected based on a second semiconductor chipsecond stacked over a package substrate.

What is claimed is:
 1. A semiconductor device comprising: at least oneflag pad configured to provide chip stack information corresponding to astack sequence of a plurality of semiconductor chips, which arestack-packaged; and an internal circuit configured to adjust a parameterof the semiconductor device based on at least one of the chip stackinformation provided from the flag pad, wherein the parameter indicatesa skew between an external clock signal and a data strobe signal.
 2. Thesemiconductor device of claim 1, wherein the internal circuit comprises:a delay locked loop configured to delay the external clock signal by adelay time controlled in response to the chip stack information andgenerate a delayed clock signal; and a data strobe signal generationunit configured to generate the data strobe signal on which a presetdelay value corresponding to the delayed clock signal is reflected. 3.The semiconductor device of claim 2, wherein the internal circuitfurther comprises: at least one input buffer unit configured to convertthe chip stack information into a set level and output resultantinformation to the delay locked loop.
 4. The semiconductor device ofclaim 2, wherein the delay locked loop comprises a replica delay havinga delay value controlled in response to the chip stack information.
 5. Asemiconductor device comprising: a package substrate having a pluralityof external connection terminals disposed on a first surface thereof anda plurality of internal connection terminals disposed on a secondsurface thereof and electrically connected with corresponding one of theexternal connection terminals; a first semiconductor chip stacked overthe second surface of the package substrate and having a first flag padfor providing first information corresponding to a stack sequence ofsemiconductor chips and a first internal circuit for adjusting aparameter of the semiconductor device by a first correction value inresponse to the first information provided from the first flag pad; anda second semiconductor chip stacked over the first semiconductor chipand having a second flag pad for providing second informationcorresponding to a stack sequence of semiconductor chips and a secondinternal circuit for adjusting the parameter by a second correctionvalue in response to the second information provided from the secondflag pad, wherein the parameter indicates a skew between the externalclock signal and the data strobe signal.
 6. The semiconductor device ofclaim 5, further comprising: a first bonding wire configured to connectan internal connection terminal for providing a power supply voltageamong the plurality of internal connection terminals with the first flagpad.
 7. The semiconductor device of claim 6, wherein the second flag padhas a floating voltage state.
 8. The semiconductor device of claim 6,wherein the first internal circuit comprises: a first delay locked loopconfigured to delay an external clock signal by a first delay time inresponse to the first information and generate a first delayed clocksignal; and a first data strobe signal generation unit configured togenerate a first data strobe signal in response to the first delayedclock signal; and wherein the second internal circuit comprises: asecond delay locked loop configured to delay the external clock signalby a second delay time in response to the second information andgenerate a second delayed clock signal; and a second data strobe signalgeneration unit configured to generate a second data strobe signal inresponse to the second delayed clock signal.
 9. The semiconductor deviceof claim 8, wherein the first internal circuit further comprises a firstinput buffer unit configured to convert the first information providedfrom the first flag pad into first internal information and output thefirst internal information to the first delay locked loop, and whereinthe second internal circuit further comprises a second input buffer unitconfigured to convert the second information provided from the secondflag pad into second internal information and output the second internalinformation to the second delay locked loop.
 10. The semiconductordevice of claim 8, wherein the first delay locked loop controls thefirst delay time using the first correction value in response to thefirst information, and wherein the second delay locked loop maintainsthe second delay time as a default value in response to the secondinformation.
 11. The semiconductor device of claim 5, furthercomprising: a second bonding wire configured to connect an internalconnection terminal for providing a power supply voltage among theplurality of internal connection terminals with the second flag pad. 12.The semiconductor device of claim 11, wherein the first and secondinternal circuits comprise first and second replica delays,respectively, and wherein a delay value of the first replica delay ismaintained as a default value in response to the first information and adelay value of the second replica delay is controlled using the secondcorrection value in response to the second information.
 13. Thesemiconductor device of claim 5, wherein the first semiconductor chipfurther comprises: a first signal pad configured to output an outputsignal of the first internal circuit; wherein the second semiconductorchip further comprises a second signal pad configured to output anoutput signal of the second internal circuit; and wherein thesemiconductor device further comprises a third bonding wire configuredto connect an internal connection terminal for output among theplurality of internal connection terminals with the first signal pad anda fourth bonding wire configured to connect the internal connectionterminal for output with the second signal pad.
 14. The semiconductordevice of claim 1, wherein the at least one flag pad is not coupled withan internal connection terminal and is in a floating state, and the chipstack information has a high impedance value.